an "environmental" toilet facility may be coming to riverside park's clay tennis courts, at west 96th street.

the plan features self-composting toilets, part of a system that would treat and compost waste on site. the facilities-which would likely include a men's room with a stall and urinal, and a ladies' room with two stalls-would run on solar power. waste would be used to fertilize a grassy area that is currently a parking lot.

a feasibility study, with preliminary drawings of the site plans, is scheduled to be presented at the april 26 meeting of community board 7's parks and environment committee. the riverside clay tennis association and riverside park fund, which are making the presentation, are seeking approval of the concept, rather than a specific design, which they hope to adjust according to feedback from both government and private sector groups.

"i can't imagine there being any objection to this plan," said mark mcintyre, the tennis association's executive director. "anyone who's used, or even come within 35 feet of one of the toilets that we use now, is aware of the public need for this."

currently, the tennis courts are served by two portable toilets, which are used by players and other park patrons. the site is not connected to the city's sewer grid because it sits between the hudson river and west side highway.

"right now, the closest facility is at the 97th street playground," mcintyre said. "but to get there, you have to go up four or five blocks, get to a spot to cross the highway, then go four or five blocks. the next closest bathroom is at the boat basin, on 79th street."

mcintyre also noted that the facilities have grown increasingly inadequate as more and more players use the courts.

"when i first started 15 years ago, we had 8,000 people sign up to use the courts, per year," he said. "now it's up to 30,000 people."

the feasibility study was done by the architectural firm cook+fox, best known for the bank of america tower at one bryant park. the plan would also call for a tennis maintenance facility, a post for court monitors and viewing stands, as well as offices for the tennis association, which currently shares space with the fund. funding would come from city and state dollars, supplemented by private donations.

the proposal, which is only in a preliminary stage, would need to be reviewed by several layers of government, including the city planning commission and both the city and state departments of environmental protection, a process that could take at least two years.